Checking the coolant level
WARNING Risk of burns from hot component parts in the engine compartment
Certain component parts in the engine compartment can be very hot, e.g. the engine, the cooler and parts of the exhaust system.
Allow the engine to cool down and only touch component parts described in the following.
If you have to carry out any work in the engine compartment, touch only the following components:
Bonnet
Engine oil filler opening cap
Washer fluid reservoir cap
Coolant expansion reservoir cap
WARNING Risk of burns when opening the bonnet
If you open the bonnet in the event of an overheated engine or fire in the engine compartment, the following situations may occur:
You may come into contact with hot gases.
You may come into contact with other escaping hot operating fluids.
Before opening the bonnet, allow the engine to cool down.
In the event of a fire in the engine compartment, keep the bonnet closed and call the fire service.
WARNING Risk of scalding from hot coolant
If you open the cap, you could be scalded.
Let the motor cool down before opening the cap.
When opening the cap, wear protective gloves and safety glasses.
Open the cap slowly to release pressure.
Allow the engine and the engine cooling system to cool down before checking the coolant level or refilling coolant.
NOTE Paintwork damage due to coolant
If coolant gets on painted surfaces, the paintwork can be damaged.
Add coolant carefully.
Remove spilled coolant.
Checking the coolant level
Coolant expansion reservoir (example)
Park the vehicle on a level surface.
Open the bonnet More.
Slowly turn the coolant expansion tank cap 
half a turn anti-clockwise and allow overpressure to escape.
half a turn anti-clockwise and allow overpressure to escape. Turn coolant expansion tank cap further and remove it.
further and remove it. Check the coolant level.
There is enough coolant in coolant expansion reservoir if the coolant reaches the MAX mark.
Top up the coolant
Refill the coolant to the MAX mark on the coolant expansion reservoir.
Only use coolant approved by Mercedes-Benz to avoid damaging the engine cooling system.
Replace coolant expansion reservoir cap and tighten in a clockwise direction.
and tighten in a clockwise direction. Start the vehicle.
After about five minutes, switch off the vehicle again and allow it to cool down.
Check the coolant level again and top up the coolant if necessary.